Working on search, itself quite challenging but while one is coding against the search API, make the life more miserable.
There is a scenario happen to me recently, while working with Full Text Query search, my result set remains to be less then 50 rows, which is very suspicious, search crawler working fine plus the search center shows the result nicely, so so..
I have just changed the row limit for my FullTextQuery to 2000 and bingo.
So the lesson from this always check the row limit, and keep to maximum, because 50 is not a good number when you are doing any listing work.
Shakir Majeed Khan